This is a proposal to understand, optimize and advance a lead candidate small molecule imino sugar forward for the management of human infection by either or both Ebola and Marburg viruses. We have identified lead imino sugars with nanomolar activity against multiple hemorrhagic fever viruses in vitro, and even in lethal models of mouse infection of Ebola and Marburg. Briefly, we achieved protection of up to 70% of the mice infected with lethal doses of either Ebola or Marburg viruses, with 25-50 milligram/kg dosing of the same imino sugar. Imino sugar N-cyclohexyl-N-(6-((2R,3R,4R,5S)-3,4,5-trihydroxy-2-(hydroxymethyl)piperidin-1-yl)hexyl)pivalamide (hexyl-pival-DNJ, 17028) and (2R,3R,4R,5S)-1-(6-(2,5-difluorophenoxy)hexyl)-2-(hydroxymethyl)piperidine-3,4,5-triol (fluoro-hexyl-DNJ, 11029) were similarly effective in both models, either as pre- or post-exposure treatment. However, only intraperitoneal (i.p.) administration studies were performed, and orally available compounds are preferred. But, DNJ containing imino sugars, such as our leads, have been associated with gastrointestinal (GI) distress, when taken orally, because of the inhibition of resident intestinal lumenal glucosidases. Therefore, pro-drug modifications to the imino sugars, to improve compound oral bioavailability and reduce effects upon the GI track, will be carried out. Compounds with the best pre-clinical profile will then be tested for advanced in vitro and in vivo Absorption, Distribution, Metabolism, Excretion and Toxicity (ADMET), and advanced efficacy studies, against both Marburg and Ebola virus infections in multiple animal models. Taken together, although our two leads could be moved forward toward development as a parenterally administered drug, the preference is for an orally available medication devoid of GI glucosidase inhibitory activity. Thus, either the current lead or a second generation prodrug will be ready for IND enabling studies, with our commercialization partner, by the end of this project.